It isn't labor, although that's bad enough. GM has too many models, plants and executives. It may need a major overhaul

When General Motors' Saturn plant was opened amid the cornfields of Spring Hill, Tenn., in 1990, it was billed as a kind of corporate nirvana where a folksy labor force and enlightened managers would happily work to produce some of the best darn American cars on the road. The plant represented a unified front against growing Japanese imports and offered the broader prospect of peace between GM and the United Auto Workers.

But last week the seething revolt that started at two GM parts plants in old-fashioned Flint, Mich., spread to this Southern paradise. The Flint strike shut off critical...